
\begin{tabular}{rrrrrrr}
\toprule
\multicolumn{1}{c}{ } & \multicolumn{3}{c}{BRS} & \multicolumn{3}{c}{QCA} \\
\cmidrule(l{3pt}r{3pt}){2-4} \cmidrule(l{3pt}r{3pt}){5-7}
N & Num. Rules & Rule Len. & Accuracy & Num. Rules & Rule Len. & Accuracy\\
\midrule
25 & 1.85 & 2.41 & 0.58 & 3.67 & 2.83 & 0.56\\
100 & 1.35 & 2.86 & 0.64 & 11.05 & 4.51 & 0.59\\
250 & 1.44 & 2.91 & 0.67 & 24.62 & 5.64 & 0.60\\
500 & 1.79 & 2.94 & 0.69 & 43.73 & 6.50 & 0.61\\
750 & 2.35 & 2.96 & 0.71 & 59.49 & 6.98 & 0.61\\
\addlinespace
1000 & 2.55 & 2.97 & 0.72 & 71.56 & 7.33 & 0.62\\
\bottomrule
\end{tabular}
